Printers equipped with a mechanism that winds an ink ribbon with the forward-and-back movement of a carriage are prevalent. Patent Literature 1 discloses one such printer equipped with a mechanism in which a ribbon is wound in only one given direction, regardless of the direction in which the carriage moves.
The printer disclosed in Patent Literature 1 is equipped with an ink ribbon winding mechanism equipped with a rack, a moving gear that moves by engaging with the rack, a gear group that engages with the moving gear, and a winding axle integrally formed with one gear in the gear group.
When the carriage moves in one direction, the moving gear rotates counter-clockwise while moving to a position that abuts (engages with) a first gear. Due to the rotation of the moving gear, the first gear rotates clockwise, causing a second gear to rotate counter-clockwise. Then, the second gear rotates counter-clockwise together with the winding axle, and the ink ribbon is wound by the winding axle.
Also, when the carriage moves in the other direction, the moving gear rotates clockwise while moving to a position that abuts (engages with) a third gear. Due to the rotation of the moving gear, the third gear rotates counter-clockwise, causing an engaged fourth gear to rotate clockwise. The fourth gear then causes the second gear to rotate counter-clockwise. Then, the second gear rotates counter-clockwise together with the winding axle, and the ink ribbon is wound by the winding axle.
Consequently, the ink ribbon is wound in the same direction regardless of the direction in which the carriage moves.
Patent Literature 1: Unexamined Japanese Patent Application Kokai Publication No. S61-182976.